Sensor semiconductor package, provided with an insert, and method for making same

ABSTRACT

A semiconductor package includes a mounting and electrical connection plate, and a semiconductor component having front and rear surfaces and including a sensor. The rear surface of the semiconductor component is attached to the mounting and electrical connection plate and the front surface is attached to the sensor. An insert is adjacent the front face of the semiconductor component and the sensor and has an access passage for exposing the sensor. A plug is in the access passage of the insert. A body of encapsulation material surrounds the mounting and electrical connection plate, the semiconductor component and the insert.

FIELD OF THE INVENTION

[0001] The present invention relates to the field of semiconductorpackages having a sensor, and in particular, to an optical, chemical ordisplacement sensor operating remotely or by contact.

BACKGROUND OF THE INVENTION

[0002] Semiconductor components having a sensor are generally mounted inpackages that are externally accessible. In the majority of cases, thesesensors need to be protected.

[0003] Semiconductor components with optical sensors are generallyinstalled in the bottom cavity of their encapsulation packages. Theseencapsulation packages often have an attached lid made of a transparentmaterial. The bottom wall of the encapsulation packages are used to makeelectrical connections external the semiconductor component. Sucharrangements require a large number of fabrication steps, and are notmulti-functional.

SUMMARY OF THE INVENTION

[0004] An object of the present invention is to improve and simplifysemiconductor devices having a sensor, and to provide a correspondingmethod for fabricating such devices.

[0005] This and other objects, advantages and features in accordancewith the present invention comprises placing in an injection mold cavitya semiconductor component, a rear face of which is attached to a frontface of mounting and electrical connection means and a front face ofwhich is attached to a sensor. The semiconductor component may furthercomprise an insert that includes an open passage in front of the sensor,and is provided with a plug for closing the open passage. The insert mayhave an end bearing on the front face of the component and around thesensor, and a front face bearing against a bottom of the cavity. Themethod may further comprise injecting an encapsulation material into thecavity for encapsulating the mounting and electrical connection means,and peripherally the semiconductor component and insert.

[0006] The method may further comprise placing an annular seal forming aspacer between the insert and the semiconductor component. The insertmay be fitted with centering fins for centering the insert in theinjection mold cavity, and the insert may be fitted with a pluginstalled in the passage thereof. The plug may be a transparent plugthat is installed in the passage after demolding.

[0007] Another aspect of the present invention is directed to asemiconductor package obtained by implementing the above describedmethod. The semiconductor package may comprise a semiconductorcomponent, a rear face of which is attached to a front face of mountingand electrical connection means and a front face of which is attached toa sensor. The semiconductor package may further comprise an insertbearing on the front face of the optical component around the sensor,and includes an open passage in front of the sensor. A plug may beinstalled in the passage of the insert. The mounting and electricalconnection means, the semiconductor component and the insert may beencapsulated with an encapsulation material.

[0008] The insert may bear on the front face of the optical componentvia an annular seal forming a spacer. The insert may advantageously beattached to the front face of the optical component by adhesive bonding.The plug may be transparent, and the plug may advantageously beintegrated in the insert. The insert may comprise, in its front face, anannular groove.

[0009] The mounting and electrical connection means may comprise a gatehaving a platform or plate for mounting the semiconductor component, andelectrical connection leads extending external the encapsulationmaterial. The mounting and electrical connection means may comprise amounting and electrical connection plate.

BRIEF DESCRIPTION OF THE DRAWING

[0010] The present invention will be better understood on studyingsemiconductor packages fitted with a sensor and their fabricationmethod, described by way of non-limiting examples and illustrated by thedrawings in which:

[0011]FIG. 1 is a cross-sectional view of a first embodiment of asemiconductor package being fabrication in accordance with the presentinvention;

[0012]FIG. 2 is a top view of the semiconductor package illustrated inFIG. 1 after fabrication;

[0013]FIG. 3 is a cross-sectional view of the semiconductor packageillustrated in FIG. 1 after fabrication;

[0014]FIG. 4 is a cross-sectional view of a second embodiment of asemiconductor package being fabrication in accordance with the presentinvention;

[0015]FIG. 5 is a cross-sectional view of a third embodiment of asemiconductor package being fabrication in accordance with the presentinvention; and

[0016]FIG. 6 is a top view, partially in cross-sectional, of thesemiconductor package illustrated in FIG. 5 after fabrication.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] With reference to FIGS. 1 to 3, a semiconductor package 1comprises a metal gate 2 which has a central platform 3 and peripheralelectrical connection leads 4. The rear face of a semiconductorcomponent 5 is attached to the front face of the platform 3 via a layerof adhesive 6. This semiconductor component 5 has, in the central partof its front face 7, a sensor 8 such as an optical sensor, for example.At the periphery of this sensor 8 are electrical connection pads 9 whichare selectively connected to the electrical connection leads 4 by metalwires 10.

[0018] In addition, the semiconductor package 1 comprises an insert 11made of metal or plastic, for example, which has an annular body 12placed perpendicularly to the semiconductor component 5. One end 13 ofthe insert 11 bears against the front face 7 of the semiconductorcomponent 5 in its region lying between the sensor 8 and the pads 9. Theinsert 11 thus determines an access passage 14 opposite the sensor 8.The insert 11 has, at the periphery of its end opposite thesemiconductor component 5, an annular cover 15 which is extendedradially by four oppositely paired fins 16 and distributed at 90° aroundthe body 12.

[0019] Having previously installed a plug 17 in the passage 14 of theinsert 11, for example by screwing until the latter comes to bearagainst an annular shoulder 14 a provided in the passage 14, theassembly described above is placed in the flat cavity 18 formed betweena lower part 19 and an upper part 20 of an injection mold 21 asillustrated in FIG. 1 and as readily understood by those skilled in theart.

[0020] The rear face of the platform 3 of the gate 2, and the front face22 of the insert 11 formed by the front face of the body 12, the frontface of the cover 15 and the front face of the fins 16 are respectivelyin contact with the parallel bottoms 23 and 24 of the cavity 17. Theparallel bottoms 23 and 24 are formed respectively in the lower part 19and the upper part 20 of the mold 21. The front face of the plug 17 mayalso be in contact with the bottom 24.

[0021] The pads 4 of the gate 2 are held between the lower and upperparts 19 and 20 of the mold 21, and protrude into the cavity 18. Theends of the fins 16 are placed in the corners of the cavity 18 adjacentits bottom wall 24, and they position the insert 11 with respect to thesemiconductor component 5. The distance between the bottoms 23 and 24 ofthe cavity 18 determines the pressing force of the rear face 13 of theinsert 11 on the front face 7 of the semiconductor component 5. Thefront face 22 of the insert 11 has an annular groove 25.

[0022] In one variation, the rear face 13 of the insert 11 could beadhesively bonded to the front face 7 of the component 5. The layer ofadhesive provides flexibility in positioning the insert 11 in the cavity18, and control of the pressing force of the insert 11 on the component5. In another variation, the cover 15 and the fins 16 could be omitted.

[0023] The injection of an encapsulation material 26 into the cavity 18of the mold 21 is then undertaken to carry out an encapsulationoperation, as readily understood by those skilled in the art. Theencapsulation material 21 surrounding the platform 3 of the gate 2, thesemiconductor component 5 and the insert 11 embeds the inner part of theleads 4 of the gate 2 and the wires 10.

[0024] By virtue of the insert 11 fitted with its plug 17, the passage14 lying in front of the sensor 8 is protected against any introductionof encapsulation material during the injection operation. In addition,the annular groove 25 forms a reservoir in case of frontal seepage.

[0025] In the semiconductor package 1 being produced, it is thenpossible to remove the plug 17 to free the passage 14 so that the sensor8 is then accessible from the outside. The sensor 8 may be an opticalsensor, for example, as shown in FIG. 3. It is then possible to installa transparent protective plug 27, which could in addition form anoptical lens in the passage 14 instead of the plug 17.

[0026] With reference to FIG. 4, a semiconductor package 28 in theprocess of being fabricated is shown, which is placed in the cavity 29of an injection mold 30. In this variation, the semiconductor component31 is attached by a layer of adhesive 32 to the front face of a mountingand electrical connection plate 33.

[0027] The insert 34 is differentiated from the insert 11 of theprevious example in that its fins 35 move away from the bottom 36 of thecavity 29 corresponding to the bottom 24 of the mold 21 of the previousexample. The fins 35 come to rest in the corners of the cavity 29 at adistance from its bottom 36.

[0028] In addition, an annular seal 40 forming a spacer is insertedbetween the rear face 37 of the body 38 of the insert 34, correspondingto the rear face 13 of the insert 11 of the previous example, and thefront face 39 of the semiconductor component 31. This seal 40 ispreferably adhesively bonded against the face 37 and against the face38, and provides a degree of flexibility in positioning the insert 34.

[0029] During injection of an encapsulation material 41 in the cavity 29of the mold 28, as in the previous example, this encapsulation materialis prevented from entering the passage 42 of the insert 34 by a plug 43installed in this passage 42 and by the seal 40. The seal 40 also makesit possible to reduce and to control the pressing force of the insert 34on the semiconductor component 31. In this variation, the fins 35 of theinsert 34 are embedded in the encapsulation material 41.

[0030] With reference to FIGS. 5 and 6, a semiconductor package 44 isshown, which is only differentiated from the semiconductor package 1described with reference to FIGS. 1 and 2 in that its insert 45 has aslot 46 made radially in its body 47 and open from one side. A plate 48,for example made of glass, is installed in the slot 46 of the insert 45and forms a plug obstructing the passage 49 of this insert, thusreplacing the plug 17 of the previous example. After injection of theencapsulation material, which is carried out in the same way as in theprevious example, the plate 48, mounted in a sealed manner, is finallyinstalled in the semiconductor package 44.

[0031] The present invention is not limited to the examples describedabove. Many embodiments are possible without departing from the scopedefined by the appended claims.

That which is claimed is:
 1. A method of fabricating a semiconductorpackage, characterized in that it consists: in placing, in an injectioncavity (18) of an injection mold (21), a semiconductor component (5), arear face of which is attached to a front face of mounting andelectrical connection means (2) and a front face of which comprises asensor (8), and an insert (11) that includes an open passage (14) lyingin front of said sensor and provided with a plug (17) closing saidpassage and that has an end (13) bearing on the front face of saidcomponent, around said sensor, and a front face (22) bearing against abottom (24) of said cavity, and in injecting an encapsulation material(26) into said cavity so as to encapsulate said mounting and electricalconnection means and, peripherally, said semiconductor component andsaid insert.
 2. The method as claimed in claim 1, characterized in thatit consists in placing an annular seal (40) constituting a spacerbetween said insert and said semiconductor component.
 3. The method asclaimed in either of claims 1 and 2, characterized in that it consistsin placing in said injection cavity an insert fitted with centering fins(16) in this cavity.
 4. The method as claimed in any one of claims 1 to3, characterized in that it consists in placing in said injection cavityan insert fitted with a plug (17, 48) installed in its passage (14). 5.The method as claimed in any one of claims 1 to 4, characterized in thatit consists, after demolding, in installing a transparent plug (27) inthe passage of said insert.
 6. A semiconductor package, obtained inparticular by implementing the method according to any one of thepreceding claims, characterized in that it comprises: a semiconductorcomponent (5), a rear face of which is attached to a front face ofmounting and electrical connection means (2) and a front face of whichcomprises a sensor (8); an insert (11) bearing on the front face of saidoptical component, around said sensor, and comprising an open passage(14) lying in front of said sensor; a plug (17) installed in saidpassage of said insert; and encapsulation means (26) for said mountingand electrical connection means, said semiconductor component and saidinsert, comprising an encapsulation material which surrounds thissemiconductor component and this insert.
 7. The package as claimed inclaim 6, characterized in that said insert (34) bears on the front faceof said optical component via an annular seal (40) constituting aspacer.
 8. The package as claimed in either of claims 6 and 7,characterized in that said insert (11) is attached to the front face ofsaid optical component by adhesive bonding.
 9. The package as claimed inany one of claims 6 to 8, characterized in that said plug (27) istransparent.
 10. The package as claimed in any one of claims 6 to 9,characterized in that said plug (48) is integrated in said insert. 11.The package as claimed in any one of claims 6 to 10, characterized inthat said insert (11) comprises, in its front face, an annular groove(25).
 12. The package as claimed in any one of claims 6 to 11,characterized in that said mounting and electrical connection meanscomprise a gate (2) having a platform or plate for mounting saidsemiconductor component and electrical connection leads extendingoutside the encapsulation material.
 13. The package as claimed in anyone of claims 6 to 12, characterized in that said mounting andelectrical connection means comprise a mounting and electricalconnection plate (33).
 14. The package as claimed in either of claims 12and 13, characterized in that the encapsulation material extends atleast in front of said plate.